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| 3 | == 2007 CERN Summer student workshop == |
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| 5 | === Exercises === |
| 6 | Discover the Higgs at the LHC: |
| 7 | * Find the best prediction for Higgs production at the LHC [http://maltoni.web.cern.ch/maltoni/TeV4LHC/index.html here]. |
| 8 | * Find the Higgs branching ratios [attachment:h-br.pdf here]. |
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| 10 | Choose a channel and investigate signal and background: |
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| 12 | 1. The 4 lepton final state: %$pp \to H\to Z Z \to e^+e^- \mu^+ \mu^-$% |
| 13 | * Signal |
| 14 | * Events: [attachment:h4l-signal.lhe.gz Parton Level] [attachment:h4l-signal.lhco.gz Detector Level] |
| 15 | * Plots: [attachment:h4l-signal-lhe.pdf Parton Level] [attachment:h4l-signal-lhco.pdf Detector Level] |
| 16 | * Background |
| 17 | * Events: [attachment:h4l.lhe.gz Parton Level] [attachment:h4l.lhco.gz Detector Level] |
| 18 | * Plots: [attachment:h4l-lhe.pdf Parton Level] [attachment:h4l-lhco.pdf Detector Level] |
| 19 | 1. The 2 lepton + missing Et final state: %$pp \to H\to W^+ W^- \to e^- \bar \nu_e \mu^+ \nu_\mu $% |
| 20 | * Signal |
| 21 | * Events: [attachment:hww-signal.lhe.gz Parton Level] [attachment:hww-signal.lhco.gz Detector Level] |
| 22 | * Plots: [attachment:hww-signal-lhe.pdf Parton Level] [attachment:hww-signal-lhco.pdf Detector Level] |
| 23 | * Background |
| 24 | * Events: [attachment:hww-background.lhe.gz Parton Level] [attachment:h4l-background.lhco.gz Detector Level] |
| 25 | * Plots: [attachment:h4l-background-lhe.pdf Parton Level] [attachment:h4l-background-lhco.pdf Detector Level] |
| 26 | 1. Top associated production %$pp \to t\bar tH$% with %$H \to b \bar b$% |
| 27 | * Signal + Background samples: |
| 28 | * Events: [attachment:ttbb.lhe.gz Parton Level] [attachment:ttbb.lhco.gz Detector Level] |
| 29 | * Plots: [attachment:ttbb-lhe.pdf Parton Level] [attachment:ttbb-lhco.pdf Detector Level] |
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| 31 | === The Challenge === |
| 32 | |
| 33 | Three "black boxes" are given, in the form of event files in the LHC Olympics format and a series of selected plots: |
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| 35 | * Box A : [attachment:A.lhco.gz Events] Plots: [attachment:A-lhe.pdf Parton level] [attachment:A.pdf Detector level] |
| 36 | * Box B : [attachment:B.lhco.gz Events] Plots: [attachment:B-lhe.pdf Parton level] [attachment:B.pdf Detector level] |
| 37 | * Box C : [attachment:C.lhco.gz Events] Plots: [attachment:C-lhe.pdf Parton lelve] [attachment:C.pdf Detector level] |
| 38 | |
| 39 | Black boxes contain only signal events. The students are asked to pair up the boxes above with the following models and also answer to the questions: |
| 40 | |
| 41 | * Model 1 : Extra Z (zp) : What its mass? Does it have Standard Model couplings to fermions? |
| 42 | * Model 2 : Heavy Scalar (h): What its mass? Is it a SM Higgs? |
| 43 | * Model 3 : Extra W (wp+ or wp-) : What its mass? Does it have Standard Model couplings to fermions? |
| 44 | |
| 45 | Useful extra information: |
| 46 | * In the plots %$H_T=\sum ||p_T^{vis}|| + E_T^{miss}$%. |
| 47 | * A SM-like Z' would decay (more or less democratically) into: jet jet (uu~,cc~,dd~,ss~,bb~), t tbar (tt~), lept+lept- (e+e-,mu+mu-,ta+ta-), neutrino anti-neutrino (ve ve~,vm vm~,vt vt~). It could also have couplings to SM W and Z, and in that case would decay in to ZZ and W+W-. |
| 48 | * An Higgs couple to particles with a strength which is proportional to the particle masses. A SM-like heavy H would decay in to t tbar (tt~), W+W-, ZZ. |
| 49 | * A SM-like W'+ would decay into: jet jet (ud~,cs~), t b (tb~), lept neutrino (e+ ve , mu+ vm, ta+ vt). It could also have couplings to SM W and Z, and in that case would decay in to ZW. |
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| 52 | -- Main.FabioMaltoni - 08 Aug 2007 |
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